The virus has struck poultry in northern Myanmar, but no people have been infected, the military-controlled government said. Lab tests conducted in the Southeast Asian country confirmed the H5N1 virus after 112 chickens died in the outbreak, the FAO said.
The H5N1 strain of bird flu has killed or forced the slaughter of tens of millions of chickens and ducks across Asia since 2003, and recently spread to Europe, Africa and the Middle East.
Health officials fear H5N1 could evolve into a virus that can be transmitted easily between people and become a global pandemic.
That has not happened yet, but at least 97 people have died from the disease worldwide, two-thirds of them in Indonesia and Vietnam, according to figures by the World Health Organization.
The virus was detected in birds in four towns outside of Mandalay, the country's second-largest city, said Jum Conix, a WHO spokeswoman in Myanmar, citing a report by the Myanmar government.
In other developments:
There was no evidence, however, of human infection in Myanmar, said Than Tun, director of the country's livestock breeding and veterinary department, a division of the Agriculture Ministry.
He said that experts were inspecting farms within a two-mile radius of where the infected birds were found, and that 800 chickens had already been slaughtered.
"We are taking all measures to control the situation," he told The Associated Press, pledging that authorities would deal with the outbreak in a "transparent manner."
Than Tun's remarks were apparently meant to ease concerns expressed by some international health officials that Myanmar's junta, which exercise tight control over the mostly state-owned mass media, would not deal openly with outbreaks of bird flu.
Laurence Gleeson, a senior official with the U.N. Food and Agriculture Organization, said testing was carried out at laboratories in Mandalay and Yangon where technicians had received training in how to detect bird flu from the FAO and other international agencies.
"We have every reason to expect there is sufficient competence (in Myanmar) to make the diagnosis," he said.
According to Than Tun, samples also were being sent to a laboratory in Australia.
The World Health Organization said it was waiting for confirmation from the Australia lab before officially declaring an outbreak in Myanmar.
At present the WTO could "only say that suspected H5N1 cases were detected," Conix said.